1. Field of the Invention
The present invention relates to an electronic timepiece wherein a plurality of information items are selectively displayed on a single optical display unit.
2. Description of Related Art
Recent digital display type electronic timepieces available on the market display time on an optical digital display unit such as a liquid crystal display unit. In a conventional digital display electronic timepiece of this type, a digital display unit is fixed on the surface of the timepiece and is constantly exposed. Therefore, even when data need not be displayed, i.e., even when no data is displayed, the digital display unit is seen from outside, resulting in an aesthetically poor appearance. Furthermore, the digital display unit may be damaged.
To solve such drawbacks, in an electronic timepiece proposed in U.S. Pat. No. 4,168,607 to Friedman, the digital display unit is housed in the watch case while time display is not needed, and the digital display unit is popped up by a switch operation and simultaneously the time is displayed.
Along with the recent trend toward a multifunctional timepiece, however, a plurality of function data such as date, day, alarm, and stopwatch data, are selectively displayed on the digital display unit in addition to the time data. When the plurality of functions are selectively displayed, the number of digits required for display differs depending on the respective functions. When time is displayed, four digits are required. For the stopwatch function, six digits are required. However, if the entire display unit is popped up and only a small number of display digits are required, some digits remain unused, resulting in an aesthetically poor appearance.
In a multifunctional timepiece of this type, the functions are switched by a push button. Therefore, a push button must be provided on the timepiece case, again resulting in an aesthetically poor appearance and poor operability.
In combination timepieces also available on the market, liquid crystal display units are provided in analog display electronic timepieces in order to provide multifunctions, such as date, day, alarm, and stopwatch data.
In a combination timepiece of this type, however, two display means are provided on a single surface. More particularly, a window exposing a digital display unit is formed within an analog display face. When such a combination timepiece is of a digital type, a digital display unit is constantly seen from outside, thus degrading the overall appearance.
In order to prevent such difficulties, as described in U.S. Pat. No. 4,444,513 to Proellochs, a digital display unit is movably provided on the analog timepiece main body. When the digital display unit is pulled out, time is displayed thereon.
When another function is to be displayed, however, the number of digits required for the display differs depending on the functions. For example, four digits are required to display time, and six digits are required to provide a stopwatch function. When the display unit is pulled out by one step for display, if the data to be displayed requires only a small number of digits, some digits remain unused, thus degrading the outer appearance.